Could silk and gold replace stitches and staples?
If you need to close up an injury or incision in human body tissue, you use sutures, staples or perhaps a surgical adhesive … right? Well, if technology that's currently being developed at Arizona State University gets commercialized, liquid silk combined with gold nanoparticles may eventually be a better way to go.
Although sutures and staples are both tried and trusted approaches to wound-closing, they can damage biological tissue, and also cause infections. While adhesives are somewhat better in those regards, they can produce toxic reactions, they don't always bond that well, and they sometimes inhibit natural healing processes by keeping cells from migrating into wounds.
An Arizona State team is developing the silk/gold sealant as an alternative.
Known as a laser-activated nanosealant (LANS), it consists of a biocompatible silk solution obtained from silkworm cocoons, mixed with microscopic gold nanorods. After the sealant is applied to a wound, a laser is shone upon it. This heats the nanorods and thus the silk as well, causing it to gently interlock with the surrounding tissue proteins, forming a firm seal. Because they're made of gold, the nanorods quickly cool after the laser is turned off, minimizing the chances of heat damage to the tissue.
The scientists have already created two types of LANS – one takes the form of a patch designed for closing wounds on organs within the body, while the other is a paste that is applied to skin wounds.
When used to seal holes on samples of pig intestines, the patch was shown to have seven times more burst-pressure strength than sutures or adhesives. And two days after the paste was used to treat superficial skin wounds on lab mice, the healed skin was found to be significantly stronger than was the case with wounds which were closed using adhesives or sutures. Additionally, the LANS produced less of an immune reaction.
"Our results demonstrated that our combination of tissue-integrating nanomaterials, along with the reduced intensity of heat required in this system is a promising technology for eventual use across all fields of medicine and surgery," says Prof. Kaushal Rege, senior author of a paper on the study. "In addition to fine-tuning the photochemical bonding parameters of the system, we are now testing formulations that will allow for drug loading and release with different medications and with varying timed-release profiles that optimize treatment and healing."
The paper was recently published in the journal Advanced Functional Materials.